Photographic objective



re al 8. Jar-1 1 Patented Feb. 17, 1931 UNITED STATES craftsman PATENT OFFICE WILLY MERTE, OF GERMANY, ASSIGNOR TO THE FIRM CARL ZEISS, F JEN'A,

GERMANY PHOTOGRAPHIC OBJECTIVE Application filed September 23 1927, Serial No. 221,592, and in Germany September 28, 1926.

The present invention relates to such photographic double objectives, corrected spherically, chromatically, astigmatically and for coma, whose halves consist each of an isolated 5 collective meniscus, facing the diaphragm, and of two members cemented together, viz., a biconcave and a biconvex member.

According to the present invention one attains a good correction, extending over a large image field, by constructing the two halves of the double objective in such a way that when using each of the same so as to receive light pencils composed each of rays which are parallel to one another and coming from the side of the meniscus through a small diaphragm lying there, the rays intersect each other in such a manner that at least with larger angles of inclination of the ray pencils relatively to the axis the sagittal and the tan ential pointsv of intersection of the rays ollow each other with both halves in opposite sense.

The annexed drawing shows as an example a double objective according to the present invention whose numerical values are given in the subjoined table for a focal length of the double objective of 100 units. The double objective shown sharply covers at a relative aperture of 1: 4.5 an image field of 65. Each of the halves may also be used slngly.

4 Thicknesses and distances n =+25.90 =5.12 n =96. dn =2.31 f: =+18.41 1 =0.75 n =I+23. din =3.48 f5 =+35.54 b1 i =2.90 Ta =--33. 12 b: =2. 80 T1 =I-22.74 (11v =3.96 T5 =18.14 1: =1.57 40 r =+77.ss av =-1.ss T10 =--25.37 dvr =5. 56

Kinds of glass I and v1 11 and v III and IV sea 41.4 61.1

I claim: Photographic double ob ective, corrected spherically, chromatically astigmatically and for coma, composed of two unsymmetrical halves, each of which consists of an isolated collective meniscus, facing the other half, and of two members cemented together of which two members one is biconcave an one blconvex, the two halves being so constructed that when using each of the same so as to receive light pencils composed each of rays which are parallel to one another and coming from the side of the men" cus through 1a small diaphragm lying therefthe rays intersect eac 0t er in sue a manner that at least with larger angles of inclinat1on of the ray pencils relatively to the axis the sagittal and the tangential points of lntersection of the rays follow each other with both halves in opposite sense.

WILLY MERTE. 

